16 CEANBEERY DISEASES. 



Jersey, Massachusetts, Nova Scotia, AVisconsin, and New York, and 

 perithecia in New Jersey and New York. 



CULTURES OF GUIGNARDIA VACCINII. 



Over 200 cultures from hyphse, pycnospores, and ascospores have 

 been made upon artificial media of various kinds. The first cultures 

 of the fungus were made from Iwphse taken from the interior of 

 scalded berries. The berries were first thoroughly washed and 

 soaked in a 1 to 1.000 solution of corrosive sublimate (HgCL). and 

 a portion of the pulp containing the fungous hyphae was transferred 

 with sterile needles to the culture medium. 



The following culture media have been used : Cylinders of pota- 

 toes and of beets ; steam-sterilized and dry-sterilized cranberry leaves 

 and cranberry fruit ; cranberry agar and cranberry gelatin, pre- 

 pared by adding various proportions of cranberry juice to agar and 

 gelatin; beef agar and sugar-beet agar; corn meal saturated Avith 

 cranberry agar; corn meal saturated with cranberr}^ gelatin; malta 

 vita saturated with cranberry agar, and corn meal saturated with 

 distilled water. It appears to grow equally well upon acid and 

 neutral media. 



We have had the greatest and most uniform success in the use of 

 corn meal and water sterilized in an autoclave for about fifteen min- 

 utes. The fungus also grow^ readily on corn meal saturated with 

 cranberry agar, corn meal saturated with cranberry gelatin, and on 

 potatoes. It grows more slowly and less luxuriantly on most of the 

 other media tried. 



Pycnidial form. — Cultures producing the pycnidial form have been 

 made from the puljD and skin of diseased fruits in thirty-eight differ- 

 ent cases and from leaves in two instances. This form has also been 

 grown from p^'cnospores. The mycelium in all cases is at first thin, 

 floccose, and white. In a few days it becomes denser and takes on a 

 bluish gra}^ .color. As the culture gets older the hyphae spread con- 

 centrically and the mycelium loses its bluish tint and becomes grayish 

 brown. Pycnidia begin to appear in four to eight days, and mature 

 pycnospores can usually be found in tweh'e to eighteen daj^s. The 

 pycnidia form a more or less continuous layer on the surface of the 

 somewhat felty subiculum formed by the mycelium. They are fre- 

 quently inconspicuous on account of the velvety surface growth of 

 hypha?, with which the mycelial layer is covered. In the majority of 

 cultures made from hypha? taken from diseased berries only jwcnidia 

 are produced, and in many instances the culture has all the character- 

 istics of growth and appearance of Guignardia rarrinif, but is either 

 entirely sterile or produces sclerotia-like bodies resembling pycnidia 

 externally but containing no spores. 



110 



